Mobile, earthworking scrapers usually include a scraper bowl having a bottom opening and a pivotal floor which opens and closes the bottom opening. A pivoting apparatus is provided which includes a pivotal mounting structure supporting the floor on the bowl and an actuator for pivoting the floor rearwardly to an open, or load discharging, position and forwardly to a closed, or loading, position. Typically, the actuator includes one or more fluid cylinders. For example, U.S. Pat. No. 3,328,903, inventors Trevor G. Campbell, et. al., issued July 4, 1967, discloses an earthworking scraper having a floor which is pivoted by means of a lever moved by a fluid cylinder.
During loading, the floor is closed and earth is loaded into the bowl, as by an auger mechanism on the scraper, so that the weight of earth imposes primarily vertical forces on the floor. In load discharge, when the floor is pivoted to an open position, vertical forces on the floor continue to be imposed by the weight of the earth remaining in the bowl. In addition, as the scraper moves over the discharged earth and a striking edge of the floor levels the discharged earth, substantial horizontally-directed forces are imposed on the floor's striking edge.
These forces place considerable stress, not only upon the floors thereof, but also upon the pivoting apparatus. Hitherto, such stresses have caused components of the pivoting apparatus to bend or twist, resulting in an undesirable reduction in life thereof.